1. Field of the Invention
The present invention relates to a conduit assembly for use in a gas flow delivery system, and, in particular, to a conduit assembly that includes a plurality of flexible segments rotatably coupled to one another to prevent torque from being transferred along the conduit assembly.
2. Description of the Related Art
Gas flow delivery systems are used to deliver a flow of gas to an airway of a subject. Such systems are typically used in the medical field to deliver gas to a patient. Examples of gas flow delivery systems in the medical field include a ventilator or respirator, which replaces or supplements a patient's respiration, and a pressure support system, which provides a flow of gas to an airway of a patient at an elevated pressure to treat a medical disorder, such as obstructive sleep apnea (OSA). Pressure support systems include, but are not limited to continuous positive airway pressure (CPAP) devices, which deliver a constant positive pressure to the airway of a patient over multiple respiratory cycles, and variable pressure devices, where the pressure of the flow of gas delivered to the patient is variable.
Variable pressure support devices include auto-titrating devices that are capable of changing a base pressure or pressure profile delivered to the patent based on a monitored condition of the patient. Other variable pressure devices change the pressure of the flow of gas during a respiratory cycle. These devices include the following: a proportional assist ventilation (PAV®), a proportional positive airway pressure (PPAP®) device, a C-Flex™ device, a Bi-Flex™ device, and a BiPAP® device manufactured and distributed by Respironics, Inc. of Pittsburgh, Pa. The BiPAP device is a bi-level pressure support system in which the pressure provided to the patient varies with the patient's respiratory cycle so that a higher pressure is delivered during inspiration than during expiration.
A typical gas flow delivery system comprises a pressure/flow generating system that produces a flow of gas for delivery to a patient and a system for communicating the flow of gas to the patient. The latter system typically includes a flexible conduit having one end coupled to the pressure/flow generating device and a second end portion that couples to an airway of patient by means of a patient interface assembly worn by the patient. The conduit, which is also referred to as an air hose or patient circuit, carries the flow of gas from the pressure generating device during operation of the system. The patient interface assembly, typically in the form of a nasal, oral, or nasal/oral mask, attached to the user via a headgear is coupled to the second end portion of the conduit to communicate the flow of gas from the patient circuit to the airway of the patient.
Conventional patient circuits are typically six feet long and have a smooth internal surface to minimize the resistance the flow of gas through the tube. A continuous helix is typically provided in the exterior of the time to protect it from collapsing. While this helix serves to provide structural support for the hose, it also induces a problem with respect to the management of the hose. In particular, the increased structural support causes any loading and twisting at one portion of the hose to be carried or transferred along the entire length of the hose. This is particularly problematic because, as noted above, one end of the patient circuit is coupled to patient interface being worn by the user. Thus, torque or twisting at one location on the conventional patient circuit is readily transferred to the patient interface.
Conventional patient interfaces are typically unable to tolerate torque being applied to them by the patient circuit. This torque can cause the patient interface to be dislodged from the user or compromise the seal between the patient interface and the surface of the user, i.e., create a leak in the gas flow system at the surface of the user. Torque on the patient interface can also cause the mask to be uncomfortable to the user by applying more force that desired to a given part of the user's face.